Ultraviolet ray irradiation apparatus for fixing printed material

ABSTRACT

In an ultraviolet ray irradiation apparatus capable of forestalling printed material jams between a paper discharge unit of a printing apparatus and a reception unit of the ultraviolet ray irradiation apparatus, a signal line for exchanging electric signals with the printing apparatus is provided, and control is performed such that rotational driving of a paper conveyance belt of the ultraviolet ray irradiation apparatus is begun upon reception of a printing drum rotation start signal or a paper feeding unit paper conveyance start signal, and the rotational driving of the belt is halted after a predetermined amount of time has elapsed following reception of a printing completion signal.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an ultraviolet ray irradiationapparatus for fixing printed material, which is used while connected toa printed material discharge port of a printing apparatus employingultraviolet curable ink (also known as UV curable ink) to irradiate animage surface of a printed material with ultraviolet rays, and moreparticularly to control of a printed material conveyance speed thereof.

2. Description of the Background Art

A stencil printer, for example, has low running costs and is capable ofprinting at high speed, and is therefore used widely for printingvarious printed materials, forms, and so on in educational institutions,public offices, organizations, hospitals, and soon. Stencil printers arealso used for printing multiple copies of printed materials such asnewspaper inserts, real estate publications, and in-house writtencommunications in private enterprises. To ensure that the stencilprinter can be operated easily by anybody at any time, a printing inkthat does not harden in air is typically employed so that there is noneed to clean the printing drum unit every time it is used. This stencilink permeates the paper so as to give the appearance of being dry, butimmediately after printing, the ink on printed material is not yet dry,and if this ink is touched, the printed image is easily spoiled. Thishas been identified as a serious problem in conventional stencilprinting apparatuses, but no proposed measures have been implementedeffectively.

A stencil printing apparatus that performs stencil printing using anultraviolet curable ink and an ultraviolet ray irradiation apparatus forirradiating the printed material of the stencil printing apparatus withultraviolet rays have been proposed as methods for improving the dryingof printed material.

For example, Japanese Utility Model Publication H4-35188 relates to astencil printing apparatus in which an ultraviolet ray irradiator isprovided above a belt conveyor of a paper discharge apparatus. Acylindrical plate cylinder performs a single revolution during engravingin order to discharge a plate, but is stationary at all other times.Hence, at all times other than when the cylindrical plate cylinderposition moves by a single revolution during engraving to discharge aplate, a solenoid is electrified and a movable slit plate is positionedin a shielding position shown in the drawings. As a result, ultravioletrays issued by an ultraviolet lamp are prevented from exiting a lamphouse.

Further, Japanese Unexamined Patent Application Publication H5-64878relates to an ultraviolet fixing apparatus which irradiates a sheet ofpaper printed by printing means for performing printing using anultraviolet curable ink with ultraviolet rays, thereby fixing the inkonto the printed paper. The ultraviolet fixing apparatus comprises paperconveyance means for conveying the printed paper separately to theprinting means, and ultraviolet ray irradiating means provided above thepaper conveyance means for irradiating the printed surface of the paperwith ultraviolet rays. The upper portion or side portion of the paperconveyance means is open between the printing means and the ultravioletray irradiating means.

In a conventional stencil printing apparatus, an ultraviolet rayirradiation apparatus is disposed in connection with a paper dischargeunit, and a printed material discharged therefrom is received andconveyed by the ultraviolet ray irradiation apparatus and thenirradiated with ultraviolet rays to cure the image forming ink thereon.

Incidentally, in a printing apparatus, the printing speed may beselected variably, in contrast to an eletrophotographic copier, andtherefore an operator sets an arbitrary printing speed. However, if thespeed at which an ultraviolet ray irradiation apparatus connecteddirectly to the printed material discharge unit of the printingapparatus receives and conveys the printed material is set at a fixedvalue, the printing speeds of the two apparatuses do not match, and as aresult, a paper jam may occur around the connecting portion. If thepaper jam occurs in close proximity to an ultraviolet ray irradiationunit, the ultraviolet ray irradiation time becomes abnormally long, andas a result, the ultraviolet lamp reaches a high temperature, causingexcessive degeneration and deformation of the printing paper and adecrease in image quality.

In a printing apparatus, the printed material is delivered by the paperdischarge unit and received by the reception unit of the ultraviolet rayirradiation apparatus, and hence it has conventionally been considereddesirable to make the discharge speed of the paper discharge unit andthe reception/conveyance speed of the ultraviolet ray irradiationapparatus reception unit identical. However, when the two speeds aremade identical, the printed material may bend due to slippage caused bya slight speed difference and the effects of the paper type and papersize. Since the connecting portion is small, a bend in the paper ishighly likely to create a paper jam.

Furthermore, the printing apparatus main body, to which the ultravioletray irradiation apparatus is connected, exists in a plurality of models,and the settable printing speeds and discharge speeds thereof may differfrom each other. Hence, a technique for performing optimal control of anoperation of the ultraviolet ray irradiation apparatus in accordancewith this plurality of models is required.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an ultraviolet rayirradiation apparatus capable of forestalling a printed material jamoccurring between a paper discharge unit of a printing apparatus and areception unit of the ultraviolet ray irradiation apparatus.

In an aspect of the present invention, an ultraviolet ray irradiationapparatus for fixing a printed material is connected to a printedmaterial discharge port of a printing apparatus and comprises a belttype conveyance device configured to aspirate a lower surface of adischarged printed material and conveying the discharged printedmaterial, a drive motor configured to drive said belt, a control deviceconfigured to control the driving of the belt, and an ultraviolet rayirradiation unit configured to irradiate an image surface of thedischarged and conveyed printed material with ultraviolet rays. Theultraviolet ray irradiation apparatus has a signal line for exchangingelectric signals with the printing apparatus, and performs control suchthat rotational driving of the belt drive motor of the ultraviolet rayirradiation apparatus is begun upon reception of a printing drumrotation start signal or a paper feeding unit paper conveyance startsignal, and the belt driving is halted after a predetermined amount oftime has elapsed following reception of a printing completion signal.

In another aspect of the present invention, an ultraviolet rayirradiation apparatus for fixing a printed material is connected to aprinted material discharge port of a printing apparatus and comprises abelt type conveyance device configured to aspirate a lower surface of adischarged printed material and conveying the discharged printedmaterial, a drive motor configured to drive the belt, a control deviceconfigured to control the driving of the belt, and an ultraviolet rayirradiation unit configured to irradiate an image surface of thedischarged and conveyed printed material with ultraviolet rays. Theultraviolet ray irradiation apparatus has a signal line for exchangingelectric signals with the printing apparatus, illuminates an ultravioletlamp upon reception of a signal indicating that a print start commandhas been issued on the printing apparatus side, and when a predeterminedamount of time has elapsed therefrom, transmits a signal to the printingapparatus side allowing rotation of a printing drum of the printingapparatus and paper conveyance by a paper feeding unit to begin.

In another aspect of the present invention, an ultraviolet rayirradiation apparatus for fixing a printed material is connected to aprinted material discharge port of a printing apparatus and comprises abelt type conveyance device configured to aspirate a lower surface of adischarged printed material and conveying the discharged printedmaterial, a drive motor configured to drive the belt, a control deviceconfigured to control the driving of the belt, and an ultraviolet rayirradiation unit configured to irradiate an image surface of thedischarged and conveyed printed material with ultraviolet rays. Theultraviolet ray irradiation apparatus receives information relating to adischarge speed of a printed material discharge device in the connectedprinting apparatus from a control device on the printing apparatus side,and controls the drive motor of the belt type conveyance device in theultraviolet ray irradiation apparatus to rotate at a higher speed thanthe discharge speed of the printed material discharge device.

In another aspect of the present invention, an ultraviolet rayirradiation apparatus for fixing a printed material is connected to aprinted material discharge port of a printing apparatus and comprises abelt type conveyance device configured to aspirate a lower surface of adischarged printed material and conveying the discharged printedmaterial, a drive motor configured to drive the belt, a control deviceconfigured to control the driving of the belt, and an ultraviolet rayirradiation unit for irradiating an image surface of the discharged andconveyed printed material with ultraviolet rays. The ultraviolet rayirradiation apparatus is provided with a sensor for detecting a tip endof the printed material discharged to the vicinity of a printed materialreception unit of the ultraviolet ray irradiation apparatus, determinesa time difference between a timing at which the sensor detects thearrival of the tip end of the printed material and a timing at which thesensor detects the arrival of a tip end of a following printed material,determines a printed material discharge speed of the printing apparatusfrom a value thereof, and controls the drive motor of the belt typeconveyance device in the ultraviolet ray irradiation apparatus to ahigher speed than the discharge speed of the printed material dischargedevice.

In another aspect of the present invention, an ultraviolet rayirradiation apparatus for fixing a printed material is connected to aprinted material discharge port of a printing apparatus and comprises abelt type conveyance device configured to aspirate a lower surface of adischarged printed material and conveying the discharged printedmaterial, a drive motor configured to drive the belt, a control deviceconfigured to control the driving of the belt, and an ultraviolet rayirradiation unit configured to irradiate an image surface of thedischarged and conveyed printed material with ultraviolet rays. Theultraviolet ray irradiation apparatus is provided with an operatingpanel unit on which a value of a set printing speed during printing inthe connected printing apparatus is input, and a control device of theultraviolet ray irradiation apparatus determines a printed materialdischarge speed from input printing speed information and controls thedrive motor of the belt type conveyance device of the ultraviolet rayirradiation apparatus to a higher speed than a discharge speed of aprinted material discharge device.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features, and advantages of the presentinvention will become more apparent from the following detaileddescription taken with the accompanying drawings, in which:

FIG. 1 is a view showing the schematic constitution of an ultravioletray irradiation apparatus and a stencil printing apparatus according tothe present invention;

FIG. 2 is a front view showing a part of an operating panel of thestencil printing apparatus;

FIG. 3 is a block diagram showing the constitution of a control systemof the ultraviolet ray irradiation apparatus and stencil printingapparatus;

FIG. 4 is a graph showing variation in a printing speed increase at thestart of printing in the stencil printing apparatus;

FIG. 5 is a front view showing a part of an operating panel of theultraviolet ray irradiation apparatus;

FIG. 6 is a view showing a part of a flowchart executed when the controlsystem of the ultraviolet ray irradiation apparatus is online;

FIG. 7 is a view showing a part of a flowchart executed when the controlsystem of the ultraviolet ray irradiation apparatus is online;

FIG. 8 is a view showing a part of a flowchart executed when the controlsystem of the ultraviolet ray irradiation apparatus is offline; and

FIG. 9 is a view showing a part of a flowchart executed when the controlsystem of the ultraviolet ray irradiation apparatus is offline.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described in detail belowwith reference to the drawings.

[1] First Embodiment

FIG. 1 shows the schematic constitution of an ultraviolet rayirradiation apparatus according to the present invention and a stencilprinting apparatus to which the ultraviolet ray irradiation apparatus isconnected.

A stencil printing apparatus 50 comprises a call-up roller 3, aseparating roller 4, and a separating pad 5 for separating printingpaper (also referred to as printed material hereafter) 2 stacked on apaper feeding table 1 into single sheets and conveying the printingpaper 2 toward a resist roller pair. The resist roller pair (constitutedby an upper resist roller 6 and a lower resist roller 7), which conveysthe single sheet of printing paper separated in the manner describedabove to a stencil printing unit at a predetermined timing, is provideddownstream of the separating pad 5, as shown by an arrow a.

Once the printing paper has been issued from the resist roller pair atthe predetermined timing, an engraved stencil base paper 8 latches thetip end thereof using a base paper damper 9 such that the printing paperis guided by a guide plate, not shown in the drawing, and conveyedtoward the stencil printing unit between a printing drum, which iswrapped around and attached to the outer periphery of a cylindricalplate cylinder 10, and a press roller 11, which rotates while pressingthe printing paper against the printing drum. The printing drum isdriven to rotate in the direction of an arrow in the drawing by adriving mechanism, not shown in the drawing.

The interior of the cylindrical plate cylinder 10 comprises an inkroller 12 that is driven to rotate, a doctor roller 13 disposeddiagonally above the ink roller 12, an ink reservoir 14 formed from asubstantially wedge-shaped gap between the ink roller 12 and doctorroller 13, and so on. Ultraviolet curable printing ink is suppliedtoward the ink reservoir 14 through an ink supply pipe 15. The ink issupplied to the inner surface of the cylindrical plate cylinder 10,which has a large number of openings, passes through these openings,passes through engraving hole portions in the stencil base paper, and isthus transferred onto the surface of the printing paper. As a result, aprinted image is formed by the ultraviolet curable printing ink.

The printing paper subjected to stencil printing is peeled away from thestencil base paper by a peeling pawl 16 and air pressure from an airdischarge fan 17, and conveyed in the leftward direction of the drawingby a paper discharge conveyance apparatus 18. Here, the paper dischargeconveyance apparatus 18 comprises a plurality of endless belts 21wrapped around a front roller 19 and a rear roller 20, a drive motor 22for driving the endless belts 21 to rotate by rotating the rear roller20, and an air suction duct 23 and an air suction fan 24 for aspiratingthe rear surface of the printing paper so that the rear surface of theprinting paper contacts the conveyor belt.

A printed material discharge port of the stencil printing apparatus 50is formed beyond the left end of the endless belt 21, and a right endopening portion of an ultraviolet ray irradiation apparatus 30 isconnected to the printed matter discharge port. Thus, the ultravioletray irradiation apparatus 30 is connected so as to be capable ofconveying printing paper delivered from the paper discharge conveyanceapparatus 18 of the stencil printing apparatus 50. The ultraviolet rayirradiation apparatus 30 comprises a belt type printed materialconveyance apparatus 31 for conveying printed material received from theright end opening portion. The printed material conveyance apparatus 31comprises a dedicated drive motor 35 for driving a plurality ofperforated endless belts 34 made of thin metal plates and wrapped arounda front roller 32 and a rear roller 33, and an air suction duct 36 andan air suction fan 37 for aspirating the lower surface (rear surface) ofthe printing paper, which is on the opposite side to the upper surface,i.e. the printed surface, to bring the lower surface of the printingpaper into contact with the perforated endless belts 34. The drive motor35 is connected to the rear roller 33 via a belt, and is controlled by acontrol apparatus 62 to be described below.

An ultraviolet ray irradiation portion, or more specifically anultraviolet ray irradiation unit 38, is provided above the printedmaterial conveyance apparatus 31 for irradiating the image surface ofthe printing paper with ultraviolet rays after the printing paper hasbeen discharged from the stencil printing apparatus 50 and conveyed bythe perforated endless belt 34. The ultraviolet ray irradiation unit 38comprises an ultraviolet lamp 39 such as a high pressure mercury lamp, ametal halide lamp, or an amalgam lamp, a reflector 40 formed from analuminum plate or the like, and a cover casing 41 provided on theoutside of the reflector 40. Although not shown in the drawing, theultraviolet ray irradiation unit 38 also comprises an air dischargepipe, a suction fan, and so on for aspirating the air in the covercasing 41 and discharging the air to the exterior of the printingapparatus after passing the air through an ozone filter.

Further, a first sensor 42 for detecting the passage of the printingpaper is provided at the front end portion of ultraviolet rayirradiation, and a second sensor 43 is provided at the rear end portionof ultraviolet ray irradiation. More specifically, the first sensor 42is an optical reflection sensor disposed within the irradiation range ofthe ultraviolet ray irradiation unit 38 on the outside and to the frontof the conveyance direction of the casing 41, and is used to detect thetip end of the printed material discharged to the vicinity of theprinted material reception unit of the ultraviolet ray irradiationapparatus 30. Meanwhile, the second sensor 43 is disposed within theirradiation range of the ultraviolet ray irradiation unit 38 on theoutside and to the rear of the conveyance direction of the cover casing41, which is indicated by an arrow b.

The printing paper conveyed by the printed material conveyance apparatus31 is irradiated with ultraviolet rays, and as a result, the ink on theimage surface thereof is cured and fixed. The printed material is thenstacked and stored on a paper discharge tray 44. The tip end portion ofthe discharged paper is stopped by an end fence 45, while the two sidefaces of the discharged paper are guided and positioned by a side fence46.

FIG. 2 shows an operating panel 51 of the stencil printing apparatus 50.In the following description, FIG. 1 will be referenced where necessary.When an original is set on an original reading apparatus 52, theinterior details of which have been omitted from the drawing, and anengraving start key 53 in FIG. 2 is pressed, a used base paper wrappedaround the outer periphery of the cylindrical plate cylinder 10constituting the main part of the printing drum is peeled away from thecylindrical plate cylinder 10 by a plate discharge apparatus 54, theinterior details of which have been omitted from the drawing, conveyedto a discharged plate storage box in the interior of the plate dischargeapparatus 54, and stored therein. Simultaneously, the original readingapparatus 52 reads the original optically and converts the read originalinto an electric signal, whereupon an engraving apparatus 55, theinterior details of which have been omitted from the drawing, engravesan image by punching holes into the stencil base paper in accordancewith the image information of the original, and then conveys theengraved stencil base paper such that the engraved base paper is wrappedaround and attached to the outer periphery of the cylindrical platecylinder 10.

Next, the required number of printed sheets is input using a numerickeypad 56, and a print start key 57 is pressed. As a result, theprinting drum is driven to rotate, and substantially simultaneously, thecall-up roller 3 and separating roller 4 of the paper feeding unit arealso driven to rotate, whereby feeding and conveyance of the printingpaper begins. The input number of printed sheets is displayed on adisplay unit 58.

A speed instruction key 59 and a speed instruction key 60 for inputtinga printing speed are provided on the operating panel 51 of the stencilprinting apparatus 50, and an operator indicates the required printingspeed here. The printing speed may be selected from five speeds, namelya first speed to a fifth speed, and the third speed is typicallyselected automatically as a standard speed when the power is switchedON.

When a higher speed than the third speed is required, the fourth speedor fifth speed is selected by pressing the key 59, and when a lowerspeed is required, the first speed or second speed is selected bypressing the key 60. Specifically, for example, the first speed is 60sheets per minute, the third speed is 90 sheets per minute, and thefifth speed is 120 sheets per minute.

FIG. 3 shows control-related constitutions of the stencil printingapparatus 50 and ultraviolet ray irradiation apparatus 30. In the firstembodiment, a central control apparatus 61 of the stencil printingapparatus 50 is constituted to be capable of exchanging requiredinformation and instructions with a control apparatus 62 of theultraviolet ray irradiation apparatus 30 connected to the printedmaterial discharge unit.

The stencil printing apparatus 50 comprises a drum unit typeidentification sensor (to be referred to hereafter as a sensor 65) fordetecting the type of a printing drum unit constituted by thecylindrical plate cylinder 10 and auxiliary members thereof, which canbe attached to and detached from the stencil printing apparatus 50.Using the sensor 65, it is possible to identify whether or not theattached printing drum unit uses ultraviolet curable ink. When theprinting drum unit attached to the stencil printing apparatus 50 usesultraviolet curable ink, the control apparatus 62 of the ultraviolet rayirradiation apparatus 30 receives information indicating that the printstart key 57 disposed on the operating panel 51 of the stencil printingapparatus 50 has been pressed, or in other words a signal indicatingthat a print start command has been issued on the printing apparatusside, and immediately illuminates the ultraviolet lamp 39 by switchingan ultraviolet lamp illumination circuit ON and begins an air suctionoperation by driving the air suction fan 37. Once a predetermined amountof time has elapsed following illumination of the ultraviolet lamp 39,the control apparatus 62 transmits signals permitting the start ofrotation of the printing drum of the printing apparatus and the start ofpaper conveyance by the paper feeding unit to the central controlapparatus 61.

Hence, when the print start key 57 is pressed, a printing drum rotationstart signal and a paper feeding unit paper conveyance start signal aregenerated by the central control apparatus 61, and as a result, theprinting drum begins to rotate and the rollers of the paper feedingunit, including the call-up roller 3 and separating roller 4, aredriven. By transmitting the printing drum rotation start signal or thepaper feeding unit paper conveyance start signal to the controlapparatus 62 over a signal line, the control apparatus 62 starts todrive the drive motor 35 to rotate at substantially the same time as itreceives the printing drum rotation start signal or paper feeding unitpaper conveyance start signal.

When printing of the predetermined number of sheets is complete, thecentral control apparatus 61 generates a printing completion signal, andthe printing completion signal is transmitted to the control apparatus62 over a signal line and received thereby. Then, after a predeterminedtime, such as the time required to discharge the final sheet of printingpaper to the paper discharge tray 44, has elapsed, the control apparatus62 halts rotation of the drive motor 35.

Thus, the belt drive start timing and drive end timing can be optimizedin relation to the printing apparatus, and since the belt is not drivenwhen not required, low noise and low power consumption can be achieved.However, the belt is driven as soon as printed material conveyancebegins, and when printing ends, the belt is not stopped until theprinted material has passed securely through the paper dischargeprocess. Therefore, the conveyance quality can be kept high.

Furthermore, signals permitting the start of rotation of the printingdrum in the printing apparatus and the start of paper conveyance by thepaper feeding unit are transmitted to the central control apparatus 61once a predetermined time has elapsed following illumination of theultraviolet lamp 39, and therefore a situation in which printing isstarted immediately after the ultraviolet lamp is illuminated such thatthe printed material passes through the ultraviolet ray irradiationapparatus 30 during lamp activation, when the light emission energy isinsufficient, thereby causing a curing deficiency, can be prevented.Accordingly, the problem of insufficient curing during the initial stageof ultraviolet lamp illumination following activation thereof can besolved. Note that when the engraving start key is pressed, the lamp canbe illuminated during the engraving period, and therefore this problemdoes not arise.

However, a small amount of time is required for the output of theultraviolet lamp 39 to reach a normal value, and therefore the controlapparatus 62 measures the waiting time using a timer provided therein.When the output of the ultraviolet lamp 39 reaches the normal value, thecontrol apparatus 62 transmits an air suction operation start OK signalto the central control apparatus 61 of the stencil printing apparatus50. The waiting time differs according to the type of lamp, but extendsfrom approximately one minute to approximately ten or more minutes.

Having received the air suction operation start OK signal, the centralcontrol apparatus 61 of the stencil printing apparatus 50 transmits adrive start signal to a printing drum rotation drive motor 63, and thentransmits a drive start signal to the paper feeding drive motor 64 fordriving the call-up roller 3 and separating roller 4 of the paperfeeding unit to rotate. Simultaneously, printing drum rotation startinformation or paper feeding start information is transmitted to thecontrol apparatus 62 of the ultraviolet ray irradiation apparatus 30.

Upon reception of this information, the control apparatus 62 immediatelybegins rotational driving of the drive motor 35 for driving theperforated endless belt 34 to rotate. As a result, the printing paper isconveyed by the paper feeding operation, image formation printing usingultraviolet curable ink is performed by the plate discharge and printingunits, the printed material is conveyed further to undergo ultravioletray irradiation in the interior of the ultraviolet ray irradiationapparatus 30, whereby the printed image is dried and fixed, and theprinted material is discharged, stacked on the paper discharge tray 44,and stored.

The central control apparatus 61 of the stencil printing apparatus 50specifies the rotation speed of the drive motor 22 for driving theendless belt 21 of the paper discharge conveyance apparatus 18 to rotatein accordance with the printing speed input using the speed instructionkeys 59, 60.

Further, the central control apparatus 61 transmits informationregarding the input printing speed or information regarding the rotationspeed of the drive motor 22 to the control apparatus 62 of theultraviolet ray irradiation apparatus 30. The control apparatus 62 canlearn the printed material discharge speed from this information, andtherefore rotationally drives the drive motor 35 to rotate theperforated endless belt 34 at a speed set slightly higher than theprinted material discharge speed.

Hence, even when speed setting on the printing apparatus side isarbitrarily variable, the ultraviolet ray irradiation apparatus side canbe driven at an optimum belt conveyance speed corresponding thereto. Asa result, sufficient ultraviolet curing can be achieved, and jamsoccurring due to mismatched conveyance speeds can be prevented.

This will now be described in further detail.

The central control apparatus 61 of the stencil printing apparatus 50drives the printing drum to rotate at the instructed printing speed, andsimultaneously instructs rotational driving of the drive motor 22 at apredetermined speed so that the endless belt 21 of the paper dischargeconveyance apparatus 18 are driven to rotate at an optimum speedcorresponding to the printing drum rotation speed. In this case, thesurface movement speed of the endless belt 21 is set in accordance withthe speed of the printing drum outer periphery.

For example, the surface movement speed of the endless belt 21 is 70 cmper second in the first speed, 105 cm per second in the third speed, and140 cm per second in the fifth speed. The central control apparatus 61of the stencil printing apparatus 50 transmits information regarding theinstructed printing speed as is to the control apparatus 62 of theultraviolet ray irradiation apparatus 30 over a signal line.Alternatively, information regarding the rotation speed of the drivemotor 22 or information regarding the surface movement speed of theendless belt 21 is transmitted to the control apparatus 62 of theultraviolet ray irradiation apparatus 30 over a signal line. The signalline is a line for exchanging electric signals between the centralcontrol apparatus 61 and control apparatus 62, and, as shown by thebi-directional arrows linking the central control apparatus 61 andcontrol apparatus 62 in FIG. 3, this information is exchanged over thesignal line.

The control apparatus 62 of the ultraviolet ray irradiation apparatus 30accesses or calculates discharge speed data relating to thecorresponding printed material from the received printing speedinformation or endless belt surface movement speed information, anddrives the drive motor 35 to rotate such that the surface movement speedof the perforated endless belt 34 in the printed material conveyanceapparatus 31 is slightly higher than the printed material dischargespeed. Incidentally, the printed material discharge speed and thesurface speed of the endless belt 21 need not be identical.

For example, the drive motor 35 is driven to rotate such that thesurface movement speed of the perforated endless belt 34 is 10% higherthan the printed material discharge speed, or more specifically 77 cmper second in the first speed, 116 cm per second in the third speed, and154 cm per second in the fifth speed. When the surface movement speed ofthe perforated endless belt 34 in the printed material conveyanceapparatus 31 and the surface movement speed of the endless belt 21 inthe paper discharge conveyance apparatus 18 are identical, a slightslip, a speed irregularity, and so on cause a bend to form in theprinted matter between the two apparatuses, and therefore the surfacemovement speed of the perforated endless belt 34 is sets lightly higherthan the printed material discharge speed to prevent this. In a suctionbelt conveyance system, the paper may slip relative to the belt speed,causing a slight delay. The amount of slippage varies according toconditions, but it has been learned through experiment and the like thatby making the surface movement speed of the perforated endless belt 34at least 5% higher than the printed material discharge speed, this delaycan be corrected.

By ensuring that the surface movement speed of the perforated endlessbelt 34 in the printed material conveyance apparatus 31 is set higherthan the surface movement speed of the endless belt 21 in the paperdischarge conveyance apparatus 18, jams caused by bends in the paper canbe prevented more reliably. This speed setting is performed in anidentical manner in the other embodiments to be described below.

On the other hand, if the surface movement speed of the perforatedendless belt 34 in the printed material conveyance apparatus 31 is setexcessively high, the printed material moves beneath the ultraviolet rayirradiation unit 38 at a high speed and in a short amount of time suchthat the total amount of energy released onto the ink of the printedimage through ultraviolet ray irradiation decreases. As a result,sufficient curing cannot be achieved. When the surface movement speed ofthe perforated endless belt 34 is set 20% higher than the printedmaterial discharge speed, the ink on the image surface can barely becured during printing in the fifth speed, and therefore this numericalvalue is set as an upper limit. As noted above, the lower limit ispreferably set at an increase of 5% in consideration of paper slippage.

In FIG. 1, the first sensor 42 for detecting passage of the printingpaper is provided at the front end portion of ultraviolet rayirradiation. The first sensor 42 is capable of detecting the timing atwhich the printed material is discharged from the stencil printingapparatus 50. When the print start key 57 has been pressed andcontinuous printed material discharge is underway, the control apparatus62 of the ultraviolet ray irradiation apparatus 30 detects the printedmaterial discharge timing from the stencil printing apparatus 50constantly using the first sensor 42.

Usually, when a paper conveyance jam occurs in the stencil printingapparatus 50, information relating thereto is transmitted to the controlapparatus 62 of the ultraviolet ray irradiation apparatus 30, and in sodoing, a slight time deviation occurs. At such a time, it is necessaryfor the control apparatus 62 of the ultraviolet ray irradiationapparatus 30 to detect the problem in the stencil printing apparatususing the first sensor 42 as early as possible.

The first sensor 42 detects every printed material discharge, andtherefore, when the first sensor 42 does not detect the next printedmaterial after a predetermined time (a required conveyance time from anarbitrary reference position to the first sensor 42, which is determinedfrom the printed material conveyance speed and conveyance distance) haselapsed relative to a timing interval set therein, it is determined thata problem has occurred on the stencil printing apparatus 50 side. Inthis case, the control apparatus 62 immediately extinguishes theultraviolet lamp 39 and halts rotation of the drive motor 35. In thethird printing speed, for example, printed material is detected onceevery 0.67 seconds.

However, when printed material is suddenly not detected for twice thattime, i.e. 1.3 seconds, it is determined that a problem has occurred. Aproblem can be predicted more quickly using this detection than using atrouble signal transmitted by the stencil printing apparatus 50. When asingle printing job is complete, the central control apparatus 61 of thestencil printing apparatus 50 transmits a printing job completion signalto the control apparatus 62 of the ultraviolet ray irradiation apparatus30.

Upon reception of this signal, the control apparatus 62 extinguishes theultraviolet lamp 39 and halts rotation of the drive motor 35. However, apredetermined time difference is provided in this process, and thereforethe control apparatus 62 extinguishes the ultraviolet lamp 39 and haltsrotation of the drive motor 35 after a slight delay.

[2] Second Embodiment

The second embodiment relates to a case in which the control apparatus62 of the ultraviolet ray irradiation apparatus 30 is incapable ofexchanging information with the central control apparatus 61 of thestencil printing apparatus 50 online. The first sensor 42 is capable ofdetecting each discharge of printed material from the stencil printingapparatus 50, and therefore the printed material discharge speed must bedetected using the detection of the first sensor 42.

A time difference is set between the timing at which the first sensor 42detects the arrival of the tip end of a printed material and the timingat which the first sensor 42 detects the arrival of the tip end of thenext printed material, and the printed material discharge speed of thestencil printing apparatus 50 is determined from the value of this timedifference. However, it must be noted that at the start of printing, theprinting speed does not reach the set value immediately, but increasesin steps. Hence, measures must be taken in recognition of the fact thatthe printing speed increases gradually over the first few sheets ofprinting paper, and the set printing speed must be determined after apredetermined number of sheets have been detected.

FIG. 4 is a graph showing variation in the printing speed increase atthe start of printing in the stencil printing apparatus 50.

For example, printing is performed on the first sheet at a low speed of40 sheets per minute since image printing has barely begun. When thesecond sheet is printed, the speed increases to 60 sheets per minute,and if the set speed is the first speed, printing continues thereafterat 60 sheets per minute. Hence, if the time difference in the timing atwhich the first sensor 42 detect the arrival of the printed material tipend still corresponds to 60 sheets per minute at the fourth sheet, thecontrol apparatus 62 can determine that the set speed is the firstspeed.

When the set speed is the third speed, the third sheet is printed at 75sheets per minute, the fourth sheet is printed at 90 sheets per minute,and thereafter, printing continues at 90 sheets per minute. Hence, ifthe time difference in the timing at which the first sensor 42 detectthe arrival of the printed material tip end still corresponds to 90sheets per minute at the sixth sheet, the control apparatus 62 candetermine that the set speed is the third speed.

When the set speed is the fifth speed, the fourth sheet is printed at 90sheets per minute, the fifth sheet is printed at 120 sheets per minute,and thereafter, printing continues at 120 sheets per minute. Hence, ifthe time difference in the timing at which the first sensor 42 detectthe arrival of the printed material tip end corresponds to 120 sheetsper minute from the sixth sheet onward, the control apparatus 62 candetermine that the set speed is the fifth speed.

Needless to say, the drive motor 35 is rotationally driven in accordancewith the printed material discharge speed, determined in the mannerdescribed above, to rotate the perforated endless belt 34 at a speed setslightly higher than the printed material discharge speed.

According to this embodiment, the speed at which the printed material isdischarged from the stencil printing apparatus can be detected even inan offline state, in which the ultraviolet ray irradiation apparatus isnot electrically connected to the stencil printing apparatus, and theultraviolet ray irradiation apparatus side can be driven at an optimumbelt conveyance speed corresponding to the printed material dischargespeed. Hence, insufficient ultraviolet curing due to an excessively highspeed can be eliminated, and jams caused by bends in the printing paperdue to an insufficient conveyance speed can be prevented.

[3] Third Embodiment

To reduce the likelihood of a jam as much as possible from the start ofprinting using a simpler method than the method described above, theperforated endless belt 34 is driven to rotate at a speed correspondingto the maximum speed of the stencil printing apparatus 50, or in otherwords a speed corresponding to the printed material discharge speed atthe maximum printing speed of the stencil printing apparatus, at thestart of printing. A time difference in the printed material tip endarrival timing between a predetermined sheet following the start ofprinting and the next sheet, for example the time difference in thetiming at which the first sensor 42 detects the arrival of the printedmaterial tip end from the fifth sheet to the seventh sheet following thestart of printed material detection, is then detected, and the setprinting speed or the printed material discharge speed is calculatedfrom the value thereof. Thereafter, the perforated endless belt 34 ofthe ultraviolet ray irradiation apparatus 30 is driven to rotateconstantly at a slightly higher speed than the printed materialdischarge speed. This method is possible because, regardless of thespeed variation at the start, the set printing speed is reached at apredetermined sheet (in this embodiment, from the fifth to the seventhsheet following the start of printed material detection).

When the control apparatus 62 of the ultraviolet ray irradiationapparatus 30 is unable to exchange information with the central controlapparatus 61 of the stencil printing apparatus 50 online, jams occurringboth during printing and after the completion of printing must bedetected by the first sensor 42.

The first sensor 42 detects every printed material discharge, andtherefore, when the first sensor 42 does not detect the next printedmaterial after a predetermined time has elapsed relative to a set timinginterval, it is determined that either a problem has occurred on theprinting apparatus side or printing is complete. In either case, thecontrol apparatus 62 extinguishes the ultraviolet lamp 39* and haltsrotation of the drive motor 35.

[4] Fourth Embodiment

Normally, the printing speed of the stencil printing apparatus 50 ispreset at the standard speed, and when no specific instruction isissued, printing is begun at this standard speed. Hence, when nospecific instruction has been input, the control apparatus 62 of theultraviolet ray irradiation apparatus 30 controls the rotation speed ofthe drive motor 22 in the belt type printed material conveyanceapparatus 31 of the ultraviolet ray irradiation apparatus 30 to aslightly higher speed than the printed material discharge speed, whichis determined from the standard printing speed of the stencil printingapparatus 50, using this printed material discharge speed as areference.

Therefore, in an offline state where the ultraviolet ray irradiationapparatus is not electrically connected to the printing apparatus, thespeed of the connected printing apparatus can be predictedstochastically without the need to input the model and set printingspeed of the connected printing apparatus one by one, and as a result,jams can be prevented from occurring at the initial stage of printing.Further, by calculating the set printing speed or printed materialdischarge speed from the time difference in the printed material tip endarrival timing while printing is underway, the ultraviolet rayirradiation apparatus side can be driven thereafter at an optimum beltconveyance speed corresponding to the printed material discharge speed.As a result, insufficient ultraviolet curing due to excessive speed canbe eliminated, and jams caused by bends in the printing paper due to aninsufficient conveyance speed can be prevented.

Needless to say, the time difference in the timing at which the firstsensor 42 detects the arrival of the printed material tip end from thefifth sheet to the seventh sheet following the start of printed materialdetection is detected, the set printing speed is determined from thevalue thereof, and thereafter, the printing speed is determinedaccording to the determination result. As regards speed variation at thestart, it is more effective to determine that the printing speed is thestandard third speed than the fifth speed in terms of curing the printedmaterial using ultraviolet ray irradiation^(i).

FIG. 5 shows an operating panel 67 of the ultraviolet ray irradiationapparatus 30. When the control apparatus 62 of the ultraviolet rayirradiation apparatus 30 is unable to exchange information with thecentral control apparatus 61 of the stencil printing apparatus 50online, a method of inputting the model type and the set printing speedof the connected stencil printing apparatus is selected in theultraviolet ray irradiation apparatus 30.

First, the models (model names) of the connectable stencil printingapparatuses are displayed on a liquid crystal display unit 69 bypressing a model selection key 68. Next, the model name of the printerthat is to perform the printing is selected by operating up and downscroll keys 70, 71, and the printer is set by pressing the modelselection key 68 again. Next, the printing speed (the set printing speedduring printing) is selected using speed keys 72, 73. The third speed isset as standard when the power is switched ON.

When a start key 74 in FIG. 5 is pressed, the ultraviolet lampillumination circuit 75 in FIG. 3 is immediately switched ON and theultraviolet lamp 39 is illuminated. Also, the air suction fan 37 isdriven such that an air suction operation is begun. A slight amount oftime is required for the output of the ultraviolet lamp 39 to reach anormal value, and therefore the waiting time is measured using a timer,and when the output of the ultraviolet lamp 39 reaches the normal value,rotational driving of the drive motor 35 is begun immediately to drivethe perforated endless belt 34 to rotate. Here, the operator switchesthe print start key 57 of the stencil printing apparatus ON.

The control apparatus 62 determines the printed material discharge speedfrom information relating to the model and printing speed (the setprinting speed during printing) set in the manner described above, anddrives the perforated endless belt 34 to rotate by driving the drivemotor 35 to rotate at a speed set slightly higher than the printedmaterial discharge speed.

Hence, even when the ultraviolet ray irradiation apparatus 30 isoffline, i.e. not electrically connected to the stencil printingapparatus 50, the problems that arise when the set printing speeddiffers according to the type of the connected printing apparatus can besolved, and by learning the type and set input speed of the connectedprinting apparatus, the printed material discharge speed can be learnedaccurately, whereby the ultraviolet ray irradiation apparatus side canbe driven at an optimum belt conveyance speed corresponding to thisspeed. As a result, insufficient ultraviolet curing due to anexcessively high speed can be eliminated, and jams caused by bends inthe printing paper due to an insufficient conveyance speed can beprevented.

Various types of stencil printing apparatuses may be connected to theultraviolet ray irradiation apparatus 30, and depending on each type,the set printing speed value and the surface movement speed of theendless belt 21 in the paper discharge conveyance apparatus 18 may vary.To set the surface movement speed of the perforated endless belt 34 inthe printed material conveyance apparatus 31 of the ultraviolet rayirradiation apparatus 30 to an optimum value at all times, the printedmaterial discharge speed of the connected stencil printer must begrasped as accurately as possible so that the surface movement speed ofthe perforated endless belt 34 can be set in accordance therewith. It istherefore desirable to know the name of the connected model and the setprinting speed.

[5] Control Flow

FIGS. 6 and 7 are views showing parts of a control system flowchart ofthe ultraviolet ray irradiation apparatus 30 according to the presentinvention. This flowchart relates to the first embodiment describedabove, in which the printing apparatus and ultraviolet ray irradiationapparatus are online and have a signal line for exchanging electricsignals.

The control apparatus 62 shown in FIG. 3 controls the ultraviolet rayirradiation apparatus 30 in the sequence to be described below, shown inFIGS. 6 and 7, by communicating with the control apparatus 61 of thestencil printing apparatus over the signal line.

[5-1] Online Control Flow

An online control flow will be described using FIGS. 6 and 7.

In a step S1, the control apparatus 62 determines whether or not theprinting drum of the stencil printing apparatus 50 uses UV curable inkby receiving information from the central control apparatus 61. When theprinting drum does not use UV curable ink, the routine advances to astep S2, where the control apparatus 62 waits for the print start key 57to be pressed. When it is determined that the print start key 57 hasbeen pressed, a series of printing processes using non-UV curable ink isexecuted, and therefore the control apparatus 62 drives the air suctionfan 37, without illuminating the UV lamp 39, in order to fix the printedmaterial (step S3), permits the stencil printing apparatus 50 to startpaper feeding via the central control apparatus 61 (step S4), and startsto drive the perforated endless belt 34 (i.e. the drive motor 22). Theroutine then advances to a step S6.

In the step S6, the control apparatus 62 waits to receive the printingjob completion signal from the central control apparatus 61. Receptionof the printing job completion signal indicates that printing iscomplete, and therefore the routine advances to a step S7, where thecontrol apparatus 62 halts the air suction fan 37 and the perforatedendless belt 34.

On the other hand, when it is determined in the step S1 that theprinting drum of the stencil printing apparatus 50 uses UV curable ink,the following process is executed to fix the printed material printedwith the UV curable ink. First, the routine advances to a step S8, wherethe control apparatus 62 waits for the print start key 57 to be pressed.Having determined that the print start key 57 has been pressed, thecontrol apparatus 62 receives printing speed information from thecentral control apparatus 61 (step S9), and determines an appropriatedrive speed of the perforated endless belt 34 for the printing speed(step S10).

Next, the control apparatus 62 illuminates the UV lamp 39 and drives theair suction fan 37 (step S11), whereupon the routine advances to a stepS12. In the step S12, the control apparatus 62 waits for activation ofthe UV lamp 39, and when a predetermined time required for activationhas passed, the routine advances to a step S13, where the controlapparatus 62 transmits a signal permitting the start of paper feeding inthe stencil printing apparatus 50 to the central control apparatus 61.

Next, in a step S14, the control apparatus 62 waits for the paperfeeding rollers, including the call-up roller 3 and separating roller 4,to be driven, and having determined that the paper feeding rollers havebeen driven, starts driving the perforated endless belt 34 (i.e. thedrive motor 22) in a step S15. The routine then advances to a step S16.

In a step S16, the control apparatus 62 waits for the first sensor 42 todetect the tip end of the printing paper, and while waiting for thisdetection, waits for a predetermined amount of time (a standard requiredtime for the printing paper to reach the first sensor 42 from anarbitrary reference position with no conveyance problems) to pass in astep S17. If the predetermined amount of time passes, the controlapparatus 62 determines that a problem such as a jam has occurred, andin a step S18, extinguishes the UV lamp 39 and halts the perforatedendless belt 34. Then, in a step S19, the problem is displayed on adisplay unit such as the operating panel 67.

When the tip end of the printing paper is detected in the step S16before the predetermined amount of time elapses in the step S17, theroutine advances to a step S20, where the control apparatus 62 continuesto illuminate the UV lamp 39 and drive the air suction fan 37. Theroutine then advances to a step S21 in FIG. 7. In the step S21, adetermination is made as to whether or not the interval at which thefirst sensor 42 detects the tip end of the printing paper has reached orexceeded a standard predetermined time interval.

While waiting for the predetermined time interval to be reached in thestep S21, the control apparatus 62 waits to receive the printing jobcompletion signal from the central control apparatus 61 in a step S22*.Upon reception of the printing job completion signal, the controlapparatus 62 waits for a predetermined amount of time (for example, astandard time required for the tip end portion of the printing paper topass through the printed material conveyance apparatus 31 after passingthrough an arbitrary reference position) to elapse in a step 23. When itis determined in the step S23 that the predetermined amount of time haselapsed, this means that the printing paper has passed out of theultraviolet ray irradiation apparatus 30, and therefore the routineadvances to a step S24, where the UV lamp 39 is extinguished and theperforated endless belt 34 is halted. Further, in a step S25, thecontrol apparatus 62 waits for a predetermined amount of time requiredfor the printing paper to be delivered onto the paper discharge tray 44to elapse, and having determined that the predetermined amount of timehas elapsed, halts the air suction fan 37 in a step S26.

On the other hand, when it is determined in the step S21 that thepredetermined time interval has been reached or exceeded, the routineadvances to a step S27, where the UV lamp 39 is extinguished and theperforated endless belt 34 is halted. Then, in a step S28, the problemis displayed on a display unit such as that of the operating panel 67.

[5-2] Offline Control Flow

FIGS. 8 and 9 are views showing parts of a control system flowchart ofthe ultraviolet ray irradiation apparatus according to the presentinvention. This flowchart relates to the second embodiment describedabove, in which the printing apparatus and ultraviolet ray irradiationapparatus are offline and do not have a signal line for exchangingelectric signals.

The offline control flow will be described using FIGS. 8 and 9.

In a step P1, a determination is made as to whether or not model settinginput (for example, input through the selection key 68 on the operatingpanel 67) has been performed. When model setting input has not beenperformed, the routine advances to a step P2. In a step P14, adetermination is made as to whether or not speed setting input (forexample, input through the speed keys 72, 73 on the operating panel 67)has been performed. When speed setting input has not been performed, theroutine advances to the step P2. In the step P2, the control apparatus62 waits for the print start key 57 to be pressed. Having determinedthat the print start key 57 has been pressed, the control apparatus 62illuminates the UV lamp 39 and drives the air suction fan 37 in a stepP3. The routine then advances to a step P4.

In the step P4, the perforated endless belt 34 is driven at a speedcorresponding to a printing paper discharge speed of 90 sheets perminute (standard printing speed). In a step P5, the control apparatus 62waits for the first sensor 42 to detect the fourth sheet of printingpaper. When the fourth sheet of printing paper has been detected, thecontrol apparatus 62 drives the perforated endless belt 34 at a speedcorresponding to a printing paper discharge speed of 120 sheets perminute (maximum printing speed) in a step P6. In a step P7, the controlapparatus 62 waits for the first sensor 42 to detect the seventh sheetof printing paper. When the seventh sheet of printing paper has beendetected, the routine advances to a step P8, where the control apparatus62 determines a discharge speed V from the detection timing differencebetween the sixth and seventh sheets. Note that the sixth and seventhsheets are conveyed at a stable speed following the elapse of theactivation time, even in the maximum fifth speed (see FIG. 4).

In a step P9, the control apparatus 62 determines whether the determineddischarge speed V is either 105 sheets per minute or 120 sheets perminute. If the discharge speed V is either one of these speeds, thecontrol apparatus 62 continues to drive the perforated endless belt 34at a speed corresponding to 120 sheets per minute in a step P10. Theroutine then advances to a step P19 in FIG. 9.

In a step P11, the control apparatus 62 determines whether thedetermined discharge speed V is either 75 sheets per minute or 90 sheetsper minute. If the discharge speed V is neither of these speeds, theroutine advances to a step P12, where the speed of the perforatedendless belt 34 is modified to a speed corresponding to a dischargespeed V of 60 sheets per minute. The routine then advances to the stepP19 in FIG. 9. If the discharge speed V is either 75 sheets or 90 sheetsper minute in the step P1, the routine advances to a step P13, where thespeed of the perforated endless belt 34 is modified to a speedcorresponding to a discharge speed V of 90 sheets per minute. Theroutine then advances to the step P19 in FIG. 9.

Meanwhile, when model setting in the step P1 and speed setting in thestep P14 have both been performed, the routine advances to a step P15,where a printed material (printing paper) discharge speed R isdetermined from the input model and speed.

Next, in a step P16, the control apparatus 62 waits for the print startkey 57 to be pressed, and having determined that the print start key 57has been pressed, illuminates the UV lamp 39 and drives the air suctionfan 37 in a step P17. The routine then advances to a step P18, where theperforated endless belt 34 is driven at a speed corresponding to thedischarge speed R. The routine then advances to the step P19 in FIG. 9.

In the step P19 in FIG. 9, the control apparatus 62 determines a value Sof the difference in the timing at which the first sensor 42 detects anNth sheet of printing paper and an (N+1)th sheet of printing paper. In astep P20, a determination is made as to whether or not the value of Shas suddenly doubled or more, and if so (i.e. if speed variation ispresent), the control apparatus 62 determines that an irregularity hasoccurred, and extinguishes the UV lamp 39 and halts the perforatedendless belt 34 in a step P21. Furthermore, either printing completionor the problem is displayed on a display unit such as the operatingpanel 67 in a step P22. In a step P23, the control apparatus 62 waitsfor a predetermined amount of time required to deliver the printingpaper to the paper discharge tray 44 to elapse, and having determinedthat the predetermined amount of time has elapsed, halts the air suctionfan 37 in a step P24.

According to the present invention described above, the followingeffects are obtained.

(1) The ultraviolet ray irradiation apparatus has a signal line forexchanging electric signals with the printing apparatus, and performscontrol such that rotational driving of the belt drive motor of theultraviolet ray irradiation apparatus is begun at substantially the sametime as a printing drum rotation start signal or a paper feeding unitpaper conveyance start signal is received, and the belt driving ishalted after a predetermined amount of time has elapsed followingreception of a printing completion signal. Thus, belt driving can bestarted and stopped at an optimum timing in accordance with the printingapparatus, and since the belt is not driven unnecessarily, noise andpower consumption can be reduced. The belt is driven as soon asconveyance of the printed material begins, and when printing ends, thebelt is not stopped until the printed material has passed securelythrough the paper discharge process. Therefore, the conveyance qualitycan be kept high.

(2) The ultraviolet ray irradiation apparatus has a signal line forexchanging electric signals with the printing apparatus, illuminates theultraviolet lamp upon reception of a signal indicating that a printstart command has been issued on the printing apparatus side, and when apredetermined amount of time has elapsed therefrom, transmits a signalto the printing apparatus side allowing rotation of the printing drum inthe printing apparatus and paper conveyance by the paper feeding unit tobegin. Hence, a situation in which printing is started immediately afterthe ultraviolet lamp is illuminated such that the printed materialpasses through the ultraviolet ray irradiation apparatus during lampactivation, when the light emission energy is insufficient, therebycausing a curing deficiency, can be prevented. Accordingly, the problemof insufficient curing during the initial stage of ultraviolet lampillumination following activation thereof can be solved. Note that whenthe engraving start key is pressed, the lamp can be illuminated duringthe engraving period, and therefore this problem does not arise.

(3) The ultraviolet ray irradiation apparatus receives informationrelating to the discharge speed of the printed material dischargeapparatus in the connected printing apparatus from the control apparatuson the printing apparatus side, and controls the drive motor of the belttype conveyance apparatus in the ultraviolet ray irradiation apparatusto rotate at a higher speed than the discharge speed of the printedmaterial discharge apparatus. Hence, even when the speed setting on theprinting apparatus side is arbitrarily variable, the ultraviolet rayirradiation apparatus side can be driven at an optimum belt conveyancespeed corresponding thereto. As a result, sufficient ultraviolet curingcan be achieved, and jams occurring due to mismatched conveyance speedscan be prevented.

(4) The ultraviolet ray irradiation apparatus is provided with a sensorfor detecting the tip end of the printed material discharged to thevicinity of the printed material reception unit of the ultraviolet rayirradiation apparatus, determines a time difference between the timingat which the sensor detects the arrival of the tip end of the printedmaterial and the timing at which the sensor detects the arrival of thetip end of the following printed material, determines the printedmaterial discharge speed of the printing apparatus from a value thereof,and controls the drive motor of the belt type conveyance apparatus inthe ultraviolet ray irradiation apparatus to a higher speed than thedischarge speed of the printed material discharge apparatus. Hence, evenwhen the ultraviolet ray irradiation apparatus is offline, i.e. notelectrically connected to the printing apparatus, the speed at which theprinted material is discharged from the printing apparatus can bedetected, and the ultraviolet ray irradiation apparatus side can bedriven at an optimum belt conveyance speed corresponding to this speed.As a result, insufficient ultraviolet curing due to an excessively highspeed can be eliminated, and jams caused by bends in the printing paperdue to an insufficient conveyance speed can be prevented.

(5) At the start of printing, the drive motor of the belt typeconveyance apparatus in the ultraviolet ray irradiation apparatus iscontrolled to a higher speed than the printed material discharge speedat the maximum printing speed of the printing apparatus, the setprinting speed or the printed material discharge speed is calculatedfrom a time difference between the printed material tip end arrivaltiming of a predetermined sheet from a predetermined printing startpoint and the printed material tip end arrival timing of the followingsheet, and thereafter, the drive motor of the belt type conveyanceapparatus of the ultraviolet ray irradiation apparatus is controlled toa higher speed than the printed material discharge speed. Hence, whenthe ultraviolet ray irradiation apparatus is offline, i.e. notelectrically connected to the printing apparatus, the discharge speedcannot be determined at the start of printing by the printing apparatus,but even so, the belt is driven at a sufficiently high speed, andtherefore, regardless of the set printing speed, jams caused by bends inthe printing paper due to an insufficient conveyance speed can beprevented. Furthermore, the set printing speed or printed materialdischarge speed is calculated from the time difference in the printedmaterial tip end arrival timing while printing is underway, andthereafter, the ultraviolet ray irradiation apparatus side can be drivenat an optimum belt conveyance speed corresponding to the printedmaterial discharge speed. Hence, insufficient ultraviolet curing due toan excessively high speed can be eliminated, and jams caused by bends inthe printing paper due to an insufficient conveyance speed can beprevented.

(6) The ultraviolet ray irradiation apparatus is provided with anoperating panel unit on which a value of the set printing speed duringprinting in the connected printing apparatus is input, and the controlapparatus of the ultraviolet ray irradiation apparatus determines theprinted material discharge speed from input printing speed informationand controls the drive motor of the belt type conveyance apparatus ofthe ultraviolet ray irradiation apparatus to a higher speed than thedischarge speed of the printed material discharge apparatus. Hence, evenwhen the ultraviolet ray irradiation apparatus is offline, i.e. notelectrically connected to the printing apparatus, the speed at which theprinted material is discharged from the printing apparatus can belearned, and the ultraviolet ray irradiation apparatus side can bedriven at an optimum belt conveyance speed corresponding to this speed.Therefore, insufficient ultraviolet curing due to an excessively highspeed can be eliminated, and jams caused by bends in the printing paperdue to an insufficient conveyance speed can be prevented.

(7) The ultraviolet ray irradiation apparatus is provided with anoperating panel unit on which a model of the connected printingapparatus is selected and input and a value of the set printing speedduring printing is input, and the control apparatus of the ultravioletray irradiation apparatus determines the printed material dischargespeed from input printing apparatus model information and printing speedinformation and controls the drive motor of the belt type conveyanceapparatus in the ultraviolet ray irradiation apparatus to a higher speedthan the discharge speed of the printed material discharge apparatus.Hence, even when the ultraviolet ray irradiation apparatus is offline,i.e. not electrically connected to the printing apparatus, the problemsthat arise when the set printing speed differs according to the type ofthe connected printing apparatus can be solved, and by learning themodel and set input speed of the connected printing apparatus, theprinted material discharge speed can be learned accurately, whereby theultraviolet ray irradiation apparatus side can be driven at an optimumbelt conveyance speed corresponding to this speed. As a result,insufficient ultraviolet curing due to an excessively high speed can beeliminated, and jams caused by bends in the printing paper due to aninsufficient conveyance speed can be prevented.

(8) When no specific instruction is input into the operating panel unit,the ultraviolet ray irradiation apparatus controls the drive motor ofthe belt type conveyance apparatus of the ultraviolet ray irradiationapparatus to a higher speed than the printed material discharge speedusing a printed material discharge speed determined from a standardprinting speed of the connected printing apparatus as a reference.Hence, when the ultraviolet ray irradiation apparatus is offline, i.e.not electrically connected to the printing apparatus, the speed of theconnected printing apparatus can be predicted stochastically without theneed to input the model and set printing speed of the connected printingapparatus one by one, and as a result, jams can be prevented fromoccurring at the initial stage of printing. Further, by calculating theset printing speed or printed material discharge speed from the timedifference in the printed material tip end arrival timing while printingis underway, the ultraviolet ray irradiation apparatus side can bedriven thereafter at an optimum belt conveyance speed corresponding tothe printed material discharge speed. As a result, insufficientultraviolet curing due to excessive speed can be eliminated, and jamscaused by bends in the printing paper due to an insufficient conveyancespeed can be prevented.

(9) The conveyance speed of the belt type conveyance apparatus in theultraviolet ray irradiation apparatus is set to be higher than thedischarge speed of the printed material discharge apparatus in theprinting apparatus by no less than 5% and no more than 20%. Hence, theultraviolet ray irradiation apparatus side can be driven within anoptimum belt conveyance speed range corresponding to the printedmaterial discharge speed, and as a result, insufficient ultravioletcuring due to excessive speed can be eliminated, and jams caused bybends in the printing paper due to an insufficient conveyance speed canbe prevented.

(10) A sensor is provided for detecting the tip end of the printedmaterial discharged to the vicinity of the printed material receptionunit of the ultraviolet ray irradiation apparatus, and when the sensordoes not detect the arrival of the tip end of the following printedmaterial after a predetermined amount of time has elapsed, rotationaldriving of the belt drive motor is halted. Hence, when a problem occurson the printing apparatus side, the problem can be detected quickly, andmeasures such as halting the belt and extinguishing the lamp can betaken immediately. Even in an offline state, where the ultraviolet rayirradiation apparatus is not electrically connected to the printingapparatus, a problem on the printing apparatus side can be detectedreliably, and the required measures, i.e. halting the belt andextinguishing the lamp, can be implemented.

Various modifications will become possible for those skilled in the artafter receiving the teachings of the present disclosure, withoutdeparting from the scope thereof.

1. An ultraviolet ray irradiation apparatus for fixing a printedmaterial, which is connected to a printed material discharge port of aprinting apparatus and comprises a belt type conveyance deviceconfigured to aspirate a lower surface of a discharged printed materialand conveying said discharged printed material, a drive motor configuredto drive said belt, a control device configured to control the drivingof said belt, and an ultraviolet ray irradiation unit configured toirradiate an image surface of said discharged and conveyed printedmaterial with ultraviolet rays, wherein said ultraviolet ray irradiationapparatus has a signal line for exchanging electric signals with saidprinting apparatus, and performs control such that rotational driving ofsaid belt drive motor of said ultraviolet ray irradiation apparatus isbegun upon reception of a printing drum rotation start signal or a paperfeeding unit paper conveyance start signal, and said belt driving ishalted after a predetermined amount of time has elapsed followingreception of a printing completion signal.
 2. The ultraviolet rayirradiation apparatus for fixing a printed material as claimed in claim1, wherein a sensor is provided for detecting a tip end of said printedmaterial discharged to the vicinity of a printed material reception unitof said ultraviolet ray irradiation apparatus, and when said sensor doesnot detect the arrival of a tip end of a following printed materialafter a predetermined amount of time has elapsed, said rotationaldriving of said belt drive motor is halted.
 3. An ultraviolet rayirradiation apparatus for fixing a printed material, which is connectedto a printed material discharge port of a printing apparatus andcomprises a belt type conveyance device configured to aspirate a lowersurface of a discharged printed material and conveying said dischargedprinted material, a drive motor configured to drive said belt, a controldevice configured to control the driving of said belt, and anultraviolet ray irradiation unit configured to irradiate an imagesurface of said discharged and conveyed printed material withultraviolet rays, wherein said ultraviolet ray irradiation apparatus hasa signal line for exchanging electric signals with said printingapparatus, illuminates an ultraviolet lamp upon reception of a signalindicating that a print start command has been issued on said printingapparatus side, and when a predetermined amount of time has elapsedtherefrom, transmits a signal to said printing apparatus side allowingrotation of a printing drum of said printing apparatus and paperconveyance by a paper feeding unit to begin.
 4. The ultraviolet rayirradiation apparatus for fixing a printed material as claimed in claim3, wherein a sensor is provided for detecting a tip end of said printedmaterial discharged to the vicinity of a printed material reception unitof said ultraviolet ray irradiation apparatus, and when said sensor doesnot detect the arrival of a tip end of a following printed materialafter a predetermined amount of time has elapsed, said rotationaldriving of said belt drive motor is halted.
 5. An ultraviolet rayirradiation apparatus for fixing a printed material, which is connectedto a printed material discharge port of a printing apparatus andcomprises a belt type conveyance device configured to aspirate a lowersurface of a discharged printed material and conveying said dischargedprinted material, a drive motor configured to drive said belt, a controldevice configured to control the driving of said belt, and anultraviolet ray irradiation unit configured to irradiate an imagesurface of said discharged and conveyed printed material withultraviolet rays, wherein said ultraviolet ray irradiation apparatusreceives information relating to a discharge speed of a printed materialdischarge device in said connected printing apparatus from a controldevice on said printing apparatus side, and controls said drive motor ofsaid belt type conveyance device in said ultraviolet ray irradiationapparatus to rotate at a higher speed than said discharge speed of saidprinted material discharge device.
 6. The ultraviolet ray irradiationapparatus for fixing a printed material as claimed in claim 5, wherein aconveyance speed of said belt type conveyance device in said ultravioletray irradiation apparatus is set to be higher than said discharge speedof said printed material discharge device in said printing apparatus byno less than 5% and no more than 20%.
 7. The ultraviolet ray irradiationapparatus for fixing a printed material as claimed in claim 5, wherein asensor is provided for detecting a tip end of said printed materialdischarged to the vicinity of a printed material reception unit of saidultraviolet ray irradiation apparatus, and when said sensor does notdetect the arrival of a tip end of a following printed material after apredetermined amount of time has elapsed, said rotational driving ofsaid belt drive motor is halted.
 8. An ultraviolet ray irradiationapparatus for fixing a printed material, which is connected to a printedmaterial discharge port of a printing apparatus and comprises a belttype conveyance device configured to aspirate a lower surface of adischarged printed material and conveying said discharged printedmaterial, a drive motor configured to drive said belt, a control deviceconfigured to control the driving of said belt, and an ultraviolet rayirradiation unit for irradiating an image surface of said discharged andconveyed printed material with ultraviolet rays, wherein saidultraviolet ray irradiation apparatus is provided with a sensor fordetecting a tip end of said printed material discharged to the vicinityof a printed material reception unit of said ultraviolet ray irradiationapparatus, determines a time difference between a timing at which saidsensor detects the arrival of said tip end of said printed material anda timing at which said sensor detects the arrival of a tip end of afollowing printed material, determines a printed material dischargespeed of said printing apparatus from a value thereof, and controls saiddrive motor of said belt type conveyance device in said ultraviolet rayirradiation apparatus to a higher speed than said discharge speed ofsaid printed material discharge device.
 9. The ultraviolet rayirradiation apparatus for fixing a printed material as claimed in claim8, wherein, at the start of printing, said drive motor of said belt typeconveyance device configured to in said ultraviolet ray irradiationapparatus is controlled to a higher speed than a printed materialdischarge speed at a maximum printing speed of said printing apparatus,a set printing speed or said printed material discharge speed iscalculated from a time difference between said printed material tip endarrival timing of a predetermined sheet from a predetermined printingstart point and said printed material tip end arrival timing of afollowing sheet, and thereafter, said drive motor of said belt typeconveyance device of said ultraviolet ray irradiation apparatus iscontrolled to a higher speed than said printed material discharge speed.10. The ultraviolet ray irradiation apparatus for fixing a printedmaterial as claimed in claim 8, wherein a conveyance speed of said belttype conveyance device in said ultraviolet ray irradiation apparatus isset to be higher than said discharge speed of said printed materialdischarge device in said printing apparatus by no less than 5% and nomore than 20%.
 11. The ultraviolet ray irradiation apparatus for fixinga printed material as claimed in claim 8, wherein a sensor is providedfor detecting said tip end of said printed material discharged to thevicinity of a printed material reception unit of said ultraviolet rayirradiation apparatus, and when said sensor does not detect the arrivalof a tip end of a following printed material after a predeterminedamount of time has elapsed, rotational driving of said belt drive motoris halted.
 12. An ultraviolet ray irradiation apparatus for fixing aprinted material, which is connected to a printed material dischargeport of a printing apparatus and comprises a belt type conveyance deviceconfigured to aspirate a lower surface of a discharged printed materialand conveying said discharged printed material, a drive motor configuredto drive said belt, a control device configured to control the drivingof said belt, and an ultraviolet ray irradiation unit configured toirradiate an image surface of said discharged and conveyed printedmaterial with ultraviolet rays, wherein said ultraviolet ray irradiationapparatus is provided with an operating panel unit on which a value of aset printing speed during printing in said connected printing apparatusis input, and a control device of said ultraviolet ray irradiationapparatus determines a printed material discharge speed from inputprinting speed information and controls said drive motor of said belttype conveyance device of said ultraviolet ray irradiation apparatus toa higher speed than a discharge speed of a printed material dischargedevice.
 13. The ultraviolet ray irradiation apparatus for fixing aprinted material as claimed in claim 12, wherein said ultraviolet rayirradiation apparatus is provided with said operating panel unit onwhich a type of said connected printing apparatus is selected and inputand a value of said set printing speed during printing is input, and acontrol device of said ultraviolet ray irradiation apparatus determinesa printed material discharge speed from input printing apparatus typeinformation and printing speed information and controls said drive motorof said ultraviolet ray irradiation apparatus to a higher speed thansaid discharge speed of said printed material discharge device.
 14. Theultraviolet ray irradiation apparatus for fixing a printed material asclaimed in claim 12, wherein, when no specific instruction is input intosaid operating panel unit, said ultraviolet ray irradiation apparatuscontrols said drive motor of said belt type conveyance device of saidultraviolet ray irradiation apparatus to a higher speed than saidprinted material discharge speed using a printed material dischargespeed determined from a standard printing speed of said connectedprinting apparatus as a reference.
 15. The ultraviolet ray irradiationapparatus for fixing a printed material as claimed in claim 12, whereina conveyance speed of said belt type conveyance device in saidultraviolet ray irradiation apparatus is set to be higher than saiddischarge speed of said printed material discharge device in saidprinting apparatus by no less than 5% and no more than 20%.
 16. Theultraviolet ray irradiation apparatus for fixing a printed material asclaimed in claim 12, wherein a sensor is provided for detecting a tipend of said printed material discharged to the vicinity of a printedmaterial reception unit of said ultraviolet ray irradiation apparatus,and when said sensor does not detect the arrival of a tip end of afollowing printed material after a predetermined amount of time haselapsed, rotational driving of said belt drive motor is halted.